package com.hmdp.service.impl;

import cn.hutool.core.bean.BeanUtil;
import cn.hutool.core.util.BooleanUtil;
import cn.hutool.core.util.StrUtil;
import com.baomidou.mybatisplus.extension.plugins.pagination.Page;
import com.hmdp.dto.Result;
import com.hmdp.dto.ScrollResult;
import com.hmdp.dto.UserDTO;
import com.hmdp.entity.Blog;
import com.hmdp.entity.Follow;
import com.hmdp.entity.User;
import com.hmdp.mapper.BlogMapper;
import com.hmdp.service.IBlogService;
import com.baomidou.mybatisplus.extension.service.impl.ServiceImpl;
import com.hmdp.service.IFollowService;
import com.hmdp.service.IUserService;
import com.hmdp.utils.SystemConstants;
import com.hmdp.utils.UserHolder;
import org.springframework.data.redis.core.StringRedisTemplate;
import org.springframework.data.redis.core.ZSetOperations;
import org.springframework.stereotype.Service;

import javax.annotation.Resource;
import java.util.ArrayList;
import java.util.Collections;
import java.util.List;
import java.util.Set;
import java.util.stream.Collectors;

import static com.hmdp.utils.RedisConstants.BLOG_LIKED_KEY;
import static com.hmdp.utils.RedisConstants.FEED_KEY;

/**
 * <p>
 *  服务实现类
 * </p>
 *
 * @author 虎哥
 * @since 2021-12-22
 */
@Service
public class BlogServiceImpl extends ServiceImpl<BlogMapper, Blog> implements IBlogService {

    @Resource
    private IUserService userService;

    @Resource
    private StringRedisTemplate stringRedisTemplate;

    @Resource
    private IFollowService followService;
    @Override
    public Result queryHotBlog(Integer current) {
        // 根据用户查询
        Page<Blog> page = query()
                .orderByDesc("liked")
                .page(new Page<>(current, SystemConstants.MAX_PAGE_SIZE));
        // 获取当前页数据
        List<Blog> records = page.getRecords();
        // 查询用户
        records.forEach(blog ->{
            this.queryBlogUser(blog);
            //查询blog是否被点赞了
            this.isBlogLiked(blog);
        });
        return Result.ok(records);
    }

    /**
     * 首页展示用户的笔记
     * @param id
     * @return
     */
    @Override
    public Result queryBlogById(Long id) {
        //1 查询blog
        Blog blog = getById(id);
        if (blog == null) {
            return Result.fail("笔记不存在");
        }
        //2 查询blog相关的用户
        queryBlogUser(blog);
        //查询blog是否被点赞了
        isBlogLiked(blog);
        return Result.ok(blog);
    }

    /**
     * 查询blog是否被点赞了，去redis中查询
     * @param blog
     */
    private void isBlogLiked(Blog blog) {
        // 1.获取登录用户
        UserDTO user = UserHolder.getUser();
        if(user.getId() == null){
            return;
        }
        Long userId = user.getId();
        // 2.判断当前登录用户是否已经点赞 key=笔记id value=用户id
        String key = "blog:liked:" + blog.getId();
        Double score = stringRedisTemplate.opsForZSet().score(key, userId.toString());
        blog.setIsLike(score != null);
    }

    /**
     * 首页笔记里面展示用户的头像和名称
     * @param blog
     */
    private void queryBlogUser(Blog blog) {
        Long userId = blog.getUserId();
        User user = userService.getById(userId);
        blog.setName(user.getNickName());
        blog.setIcon(user.getIcon());
    }

    /**
     * 点赞功能
     * @param id 博客id
     * @return
     */
    @Override
    public Result likeBlog(Long id) {
        // 1.获取登录用户
        Long userId = UserHolder.getUser().getId();
        // 2.判断当前登录用户是否已经点赞 key=笔记id value=用户id
        String key = BLOG_LIKED_KEY + id;
        Double score = stringRedisTemplate.opsForZSet().score(key, userId.toString());
        //3.如果未点赞，可以点赞
        if (score == null) {
            //3.1 数据库点赞数+1
            boolean isSuccess = update().setSql("liked = liked +1").eq("id", id).update();
            //3.2 保存用户到Redis的set集合
            if (isSuccess) {
                stringRedisTemplate.opsForZSet().add(key, userId.toString(),System.currentTimeMillis());
            }
        }else {
            //4.如果已点赞，取消点赞
            //4.1 数据库点赞数-1
            boolean isSuccess = update().setSql("liked = liked -1").eq("id", id).update();
            if(isSuccess){
                //4.2 把用户从Redis的set集合移除
                stringRedisTemplate.opsForZSet().remove(key,userId.toString());
            }
        }
        return Result.ok();
    }

    /**
     * 实现查询top5的用户
     * @param id
     * @return
     */
    @Override
    public Result queryBlogLikes(Long id) {
        String key = BLOG_LIKED_KEY + id;
        //1 查询top5点赞用户 zrange key 0 4
        Set<String> top5 = stringRedisTemplate.opsForZSet().range(key, 0, 4);
        if(top5 == null || top5.isEmpty()){
            return Result.ok(Collections.emptyList());
        }
        //2 解析出用户id,现在这个top5是字符串，要将其变为Long类型
        List<Long> ids = top5.stream()
                .map(Long::valueOf)
                .collect(Collectors.toList());
        //3 根据用户id 查询用户 where id in (5,1) order by field(id,5,1)
        //将User转成UserDTO
        String idStr = StrUtil.join(",",ids);
        List<UserDTO> userDTOS = userService.query()
                .in("id",ids).last("order by field(id,"+idStr+")").list()
                .stream()
                .map(user -> BeanUtil.copyProperties(user, UserDTO.class))
                .collect(Collectors.toList());
        return Result.ok(userDTOS);
    }

    @Override
    public Result saveBlog(Blog blog) {
        //1 获取登录用户
        UserDTO user = UserHolder.getUser();
        blog.setUserId(user.getId());
        //2 保存探店博文
        boolean isSuccess = save(blog);
        if (!isSuccess) {
            return Result.fail("新增笔记失败");
        }
        //3 查询笔记作者的所有粉丝 select * from tb_follow where follow_user_id = ?
        List<Follow> follows = followService.query().eq("follow_user_id", user.getId()).list();
        //4 推送笔记id给所以粉丝
        for (Follow follow : follows) {
            //获取粉丝id
            Long userId = follow.getUserId();
            // 推送给粉丝
            String key = FEED_KEY + userId;
            //粉丝id:博客id
            stringRedisTemplate.opsForZSet().add(key, blog.getId().toString(), System.currentTimeMillis());
        }
        //5 返回id
        return Result.ok(blog.getId());
    }

    /**
     * 滚动查询，展示博主推送的笔记， 新发布的滚动查询查不到，但是往上滚，前端做了处理，就是刷新重新查询，开始位置在当前最新位置
     * @param max
     * @param offset
     * @return
     */
    @Override
    public Result queryBlogOfFollow(Long max, Integer offset) {
        //1 获取当前用户
        Long userId = UserHolder.getUser().getId();
        //2 查询收件箱
        String key = FEED_KEY + userId;
        Set<ZSetOperations.TypedTuple<String>> typedTuples = stringRedisTemplate
                .opsForZSet().reverseRangeByScoreWithScores(key, 0, max, offset, 2);
        if(typedTuples == null  || typedTuples.isEmpty()){
            return Result.ok();
        }
        //3 解析数据：blogId、minTime(时间戳)、offset
        List<Long> ids = new ArrayList<>(typedTuples.size());
        long minTime = 0;
        int count = 1;
        for (ZSetOperations.TypedTuple<String> tuple:typedTuples){
            //获取id
            String idStr = tuple.getValue();
            ids.add(Long.valueOf(idStr));

            //获取分数（时间戳）
            long time = tuple.getScore().longValue();
            if(time == minTime){
                count++;
            }else {
                minTime = time;
                count=1;
            }
        }
        //4 根据id查询blog
        String idStr = StrUtil.join(",",ids);
        List<Blog> blogs = query().in("id",ids).last("order by field(id,"+idStr+")").list();

        for (Blog blog : blogs) {
            //2 查询blog相关的用户
            queryBlogUser(blog);
            //查询blog是否被点赞了
            isBlogLiked(blog);
        }
        //5 封装并返回
        ScrollResult r = new ScrollResult();
        r.setList(blogs);
        r.setOffset(offset);
        r.setMinTime(minTime);

        return Result.ok(r);
    }
















    /**
     * 点赞功能
     * @param id 博客id
     * @return
     *//*
    @Override
    public Result likeBlog(Long id) {
        // 1.获取登录用户
        Long userId = UserHolder.getUser().getId();
        // 2.判断当前登录用户是否已经点赞 key=笔记id value=用户id
        String key = "blog:liked:" + id;
        Boolean isMember = stringRedisTemplate.opsForSet().isMember(key, userId.toString());
        //3.如果未点赞，可以点赞
        if (BooleanUtil.isFalse(isMember)) {
            //3.1 数据库点赞数+1
            boolean isSuccess = update().setSql("liked = liked +1").eq("id", id).update();
            //3.2 保存用户到Redis的set集合
            if (isSuccess) {
                stringRedisTemplate.opsForSet().add(key, userId.toString());
            }
        }else {
            //4.如果已点赞，取消点赞
            //4.1 数据库点赞数-1
            boolean isSuccess = update().setSql("liked = liked -1").eq("id", id).update();
            if(isSuccess){
                //4.2 把用户从Redis的set集合移除
                stringRedisTemplate.opsForSet().remove(key,userId.toString());
            }
        }
        return Result.ok();
    }*/
}
